The present invention relates to a digitally compatible servomotor with a reversible digital stepping motor, preferably a hydraulic or pneumatic stepping motor.
Hydraulic servomotors are known in many different versions. The German Patent Publication (DOS) No. 2,413,946 discloses, for example, an apparatus the actuating mechanism of which is connected to a tripping device by a single control conduit. The tripping device is connected to the working member through a pressure line or conduit. The tripping device comprises a rotationally movable piston arranged in a cylinder wherein said piston rotates stepwise about its longitudinal axis. Each rotational step positioning of the piston alternately releases a connection between the control conduit and a pressure line. Such a servomotor arrangement is not only expensive to construct, the resolution capability of the servocylinder is not optimal because of the relatively large stepping increments.
Hydraulic gearing mechanisms for effecting alternating movements are also known already. The German Patent Publications (DOS) No. 2,502,832 and (DOS) No. 2,502,833, for example, disclose such an arrangement for effecting reversible movements. The arrangement causes an indirect reversing by means of a pressure medium circuit which is supplied by an auxiliary pressure medium source having a constant delivery capacity. The pressure medium circuit adjusts the reversing mechanism of a pump by means of a servovalve. The manufacturing costs of such an apparatus are still too large in view of the limited exactness which may be attained.